For Robert Collier - Ram Mixing - AMD & Gigabyte - According to Manual: mb_manual_ga-990fx-gaming_v1.1_e.pdf"Due to CPU limitations, read the following guidelines before installing the memory in Dual Channel mode.

When enabling Dual Channel mode with two or four memory modules, it is recommended that memoryof the same capacity, brand, speed, and chips be used and installed in the same colored sockets. Foroptimum performance, when enabling Dual Channel mode with two memory modules, we recommendthat you install them in the DDR3_1 and DDR3_2 sockets."

From Duane Hendricks, Re: Mel Babb - Houston Public Library - Houston, We Have Lynda! "Here are the instructions for signing on to Lynda. Set up an account and scroll through course offerings. They have a wide variety of courses from beginner level to expert."